Polarization controllers are used in many applications relating to fiber-optic test and measurement. These controllers typically utilize piezoelectric transducers as mechanical “squeezers” to alter the state of polarization (“SOP”) in an optical fiber. The controllers then monitor the SOP to generate a signal that is in turn used in feedback to control or stabilize SOP. The optical sensors used to monitor SOP generally include polarization optics, photodiodes, and/or complex signal processing electronics used to process signals based, at least in part, on SOP.
Accordingly, one disadvantage with polarization controllers in the prior art is that they process information about SOP, and that this information is in turn used in feedback control of SOP. This feedback is slow and often involves complex feedback electronics; consequently the operation of the controller is slow. Since polarization controllers provide increasing benefit to applications with increasing speed in controlling SOP, there is a need for more efficient and speedier polarization controllers.
The invention solves the afore-mentioned problems, in one object, by controlling SOP through monitoring and controlling forces applied to the fiber, and without feedback of SOP information. Other objects of the invention are apparent within the description that follows.